Some freshwater algae have lower (<130 osmol m-3) intracellular osmolarities than most others (>180 osmol m-3). Low osmolarities are related to the presence of flagella and the low energy cost of active water efflux following downhill water influx unconstrained by cell walls covering the plasmalemma, and the low resource cost of cell wall synthesis with the same mechanical degree of safety. One consequence of low intracellular osmolarity is limitation on the concentration of metabolites, that is, substrates and products of enzyme activity. Models of the flux through metabolic pathways, and hence the specific growth rate, using steady-state concentrations of enzymes and metabolites have involved organisms with intracellular metabolite osmolarities >280 osmol m-3, where the metabolite concentrations are much greater than the total osmolarity of some freshwater algae. Since the protein concentration (mol m-3) in the cells and the specific growth rates of freshwater cells with low and with higher intracellular osmolarity are highly similar, the models of trade-offs between enzyme and metabolite concentrations for cells with high intracellular osmolarity need modification for cells with low intracellular osmolarity. The soluble free-radical scavenger ascorbate can constitute as little as 0.2% of the low intracellular metabolite concentration (mol m-3) of low-intracellular-osmolarity cells.
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http://dx.doi.org/10.1093/jxb/ery254 | DOI Listing |
Nat Commun
January 2025
Center for Physics and Chemistry of Living Systems, Tel Aviv University, Tel Aviv, Israel.
Propagation of membrane tension mediates mechanical signal transduction along surfaces of live cells and sets the time scale of mechanical equilibration of cell membranes. Recent studies in several cell types and under different conditions revealed a strikingly wide variation range of the tension propagation speeds including extremely low ones. The latter suggests a possibility of long-living inhomogeneities of membrane tension crucially affecting mechano-sensitive membrane processes.
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View Article and Find Full Text PDFJ Am Chem Soc
January 2025
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
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View Article and Find Full Text PDFBiochem Biophys Res Commun
January 2025
Integrated Bioscience Section, Graduate School of Science and Technology, Shizuoka University, Shizuoka, 422-8529, Japan; Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka, 422-8529, Japan; Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, 422-8529, Japan. Electronic address:
Most antimicrobial peptides (AMPs) induce membrane damage such as pore formation in bacterial cells, resulting in rapid cell death. On the other hand, bacterial cells have a large intracellular turgor pressure, i.e.
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